The 19th century artist and naturalist John James Audubon is best known for The Birds of America, a ground-breaking series of 435 lavish, life-sized, hand-coloured plates of the continent’s avifauna. Remarkably, almost every one of Audubon’s watercolour studies for this legendary work still survives. Over the next few months, the public can get to see around 130 of the originals at the New York Historical Society on the west side of Central Park.

Audubon’s Aviary: Parts Unknown is the second in a series of three exhibitions hosted by the NYHS to show off Audubon's watercolours (purchased from his widow in 1863) in the order in which he painted them. The first installment appeared last year; the final episode will come in 2015.

Audubon was a stickler for accuracy, using specimens (many of which he collected) to depict his ornithological subjects in unparalleled detail. According to the exhibition blurb, “the watercolors possess a starling immediacy and a freshness that underline his genius in linking natural history and art, as well as a respect for the environment.” Crucially, Audubon also painted his birds to scale, using a system of wires and pins to arrange each specimen in a life-like posture from which he could transfer its image onto paper. When painting the largest birds, this meant using huge sheets, almost one metre from top to bottom.

Most of the birds that appear in the current exhibition are waders (Atlantic puffin, mallard, white ibis, American oystercatcher, black-legged kittiwake, killdeer, whooping crane, northern pintail, and so on). But there a few that aren’t. One of them – the golden eagle – is particularly interesting.

Audubon’s muse for this painting was an injured adult that he purchased in Boston. It took him weeks to pluck up the courage to kill it.

At times I was half inclined to restore to him his freedom, that he might return to his native mountains; nay, I several times thought how pleasing it would be to see him spread out his broad wings and sail away towards the rocks of his wild haunts; but then, reader, some one seemed to whisper that I ought to take the portrait of the magnificent bird, and I abandoned the more generous design of setting him at liberty, for the express purpose of shewing you his semblance.

In the end, Audubon resorted to “a method always used as the last expedient,” one which he described in his Ornithological Biography. “I thrust a long pointed piece of steel through its heart, when my proud prisoner instantly fell dead, without even ruffling a feather.”

The artist in buckskins, inching his way across the background of his study of the golden eagle. John James Audubon's 1833 watercolor model for the golden eagle (
Aquila chrysaetos), Havell pl. 181. Photograph: New-York Historical Society

Unusually, Audubon painted himself into the background of this watercolour, dressed as a woodsman, inching his way over a ravine, with a dead eagle strapped to his back. But when it came to copying this image for The Birds of America, Audubon’s London-based engraver Robert Havell Jr. left the artist out of the picture.